The present invention relates to an image forming apparatus having a sheet cassette detachably assembled to a main body portion of the apparatus for feeding each one of a sheets to an image forming section, and more particularly, to the image forming apparatus which facilitates removal of a jamming sheet.
In a conventional image forming apparatus of this kind, various proposals have been made in order to provide a mechanism for removing a jamming sheet if sheet jamming occurs in an internal portion of the apparatus. One example of such conventional arrangement is disclosed in a Japanese Patent Publication Hei 2-31465.
According to the disclosed image forming apparatus, are provided a sheet cassette provided detachably from a main body portion, a pair of rollers for nippingly feeding a sheet fed from the sheet cassette toward an image forming section, and a pair of guide plates provided spacedly from each other by a predetermined distance for defining therebetween a sheet feed path.
One of the rollers is supported on the main body portion, whereas the other roller is supported by the sheet cassette. Further, one of the guide plates is supported on the main body portion and other guide plate is supported on the sheet cassette.
If sheet jamming occurs in the above described image forming apparatus, the sheet cassette is detached from the main body portion, so that a space between the pair of rollers and a space between the pair of the guide plates are increased to provide an open space for facilitating removal of the jammed sheet.
However, in the conventional image forming apparatus, since the above described other roller and other guide plate are supported on the sheet cassette, distance between the pair of guide plates may be varied dependent on assembling condition of the sheet cassette with respect to the main body portion. If the distance is reduced, the sheet may be easily engaged with the guide plate, which leads to the sheet jamming. Further, sheet nipping force by the pair of rollers may be changed. If the nipping force is reduced, sheet slippage may occur relative to the rollers. Therefore, it becomes impossible to feed the sheet to a desired position, to thereby cause sheet jamming.